Inside an industrial butcher shop, a smoke tube boiler set at 1 tonne/hour of steam exploded. According to its specifications, the boiler had a capacity of 2,790 litres, a heating surface area of 27 m² and was burning domestic fuel oil. Installed in 1979 to supply 5 pressure cookers, it had been rated at 10 bar. A whistling sound was heard at the level of the valve assemblies just before the explosion, which blasted the 200-m² building. Three employees were killed instantly (a body was found 250 m away along with the front boiler plate), 3 others were injured, one of whom seriously. The boiler frame (weighing 3 tonnes) was projected 150 m northward, while the firebox tube and a hot water tank landed 200 m to the south. The boiler, which had been off and drained for maintenance (relief valve, drainage tap) 3 days prior, was restarted the very same morning. One possible cause of this accident would have been the untimely and inappropriate filling of the heating unit with cold water, triggering a sudden vaporisation against the heating tube, which had already been heated to high temperature. An expert’s appraisal released in 1995 indicated that partial draining of the firebox tube might have led to the observed state of damage strictly from an energy standpoint. This report however did not draw the conclusion that such draining was in fact the actual cause.